In April 2000, we reviewed the details of how light transmission and reflectance can be used to produce coatings. The process details were discussed to show how the Multicell, specialty software, inline mixer, process configuration, etc. produce coatings. This combined technology allows one to mix various components of the coating in the desired proportion at all times while it is measuring and controlling its tonality, strength, physical properties and composition to deliver the desired quality product.

Since measuring and adjustment of the product specification is done in liquid, the effect of all adjustments is immediate and results are instantaneous. This significantly influences each of the factors mentioned in Table 1. We are able to change the type and color of coating produced in few minutes with almost no waste and no off-specification product.

Figure 1 is a simple schematic of our technology. The technology measures light transmission and reflection of the coating being produced. Liquid passes between two parallel plates, and the light is transmitted through the film. Plates move to create a film.

The distance between the plates varies in 10-3,000 microns, creating a liquid film. We find the best path length (film thickness) to analyze the liquid. The wavelengths that are not absorbed pass through and are read by the spectrophotometer to create a three-dimensional electronic fingerprint. Fig. 2 is a typical electronic fingerprint.

Our capability to vary the path length allows us to measure color for opaque and transparent fluids. We create an electronic standard for each component used to manufacture the coating. Passing the standard final coating creates a three-dimensional electronic fingerprint, and this print is matched in the manufacturing process to produce a product to specification.

Once the electronic print of each coating component has been created, we mix these in any desired ratio to create a coating. Each such coating has its own electronic fingerprint and the software can duplicate the print by automatically adjusting the flow of each component. The benefit of the technology is that no sampling is necessary. The testing is done in liquid at the actual use strength and all of the off line testing time is eliminated. We continuously test every 30 seconds. All corrections are instantaneous. Thus, each packaging unit is exactly same.

Multicell measures transmission and reflection. Light travels in two paths. One path is used as reference, and the second path is used to measure transmission or reflection. For reflection, the path length is adjusted to measure standard reflection or reflection over black and white backgrounds (contrast ratio-hiding power).

Table 2 presents some of the actual results based on the formula calculated by the system. Each iteration represents a cycle for the sample to pass through the system to meet the product specification. The color difference is the reading from the standard after a spray out. The strength measured by the conventional mode is shown in the last column. Batch 1 iteration 2 indicates that the De is 0.35 from standard with 1.48- % deviation from standard. After the third iteration, De is 0.1 and strength has 0.82- % deviation from standard. Such accuracy, repeatability and speed are difficult to achieve using conventional technology.

Since our technology eliminates use of liquid standards, coating companies can develop all the standards at one place and transmit the electronic standards to any of their manufacturing facilities and produce the same product any place in the world. The electronic finger print concept is similarly used to correlate the particle size of dispersions. This technology effectively produces the exact same product time after time without taking a sample off-line and eliminates the error induced by humans, maximizing asset utilization.

It is well known that continuous processing is much more profitable than the batch processing. Our technology can be used in a batch/continuous mode but can produce a small batch of the desired product because we can switch raw materials to produce the desired product. It can be very easily implemented in an existing plant thereby minimizing investment.

As the volume of the vessel needed to blend various raw materials is small, we can very conveniently control the production volume of the final product. This allows versatility and flexibility and we accomplish this with almost zero waste. We are able to measure and correct color, its strength, hiding power, transparency, tonality, viscosity and density. This is a complete system to produce product of highest quality and consistency that cannot be achieved with the conventional technology. Our technology can be used to develop new products, optimize existing products, reduce time to market and product raw materials costs, and improve profitability.

FINANCIAL BENEFITS:

The technology impacts each of the areas mentioned Table 4 of any coatings business. We estimate the profitability of a company can be improved by about 15 to 25 percent.

The technology presented is proven and commercial. We believe that implementation of this technology will have a significant impact on the profitability of coatings businesses and will lead to new innovations which will further increase profitability of companies.
 
REFERENCES

1. Rogério A., Peixoto C. A. L. "Breakthrough in the paint industry" European Coatings Journal 738, October 1998

2. Malhotra G. "Continuous vs. Batch Manufacturing" Paint and Coatings Industry 100, February 1999

3. Malhotra G. "The Coating IndustryÕs Challenge for the New Millennium" Modern Paint and Coatings 60, October 1999

4. Pfeil P. R. "Tinting strength adjustment using Light Transmission" Paint and Coatings Industry 76, April 2000

Modern Paint & Coatings, 22-24, February 2001

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